Knowing how much RAM or Memory you need for editing your Photos in Photoshop can be quite tricky at times because there are so many factors to keep in mind.
This is why I have put together this overview guide that will hopefully answer all your questions about RAM/Memory usage when Editing Images.
First of all, the total Memory usage can be split up into 2 main parts:
- How much RAM does your Photo Editing Software need?
- How much RAM does the rest of your typical System need to run stable.
Lets start with the second one so we have that out of the way.
How much RAM does a typical Computer need to run?
To make this easier, I’ll describe an average Photo Editors Computer. It runs Win 10, usually has a browser such as Chrome open with some tabs, an Email Software and a Windows Photo-Viewer.
Chrome is using 1.3 GByte, the Foto Viewer about 250 MByte, My Email Software another 125 MByte and so on. Lets take a look what Win 10 uses with only these 3 additional Programs started:
6 GByte of RAM is used, just so the System and some Standard programs can run.
Now that we know how much RAM a typical System uses just to run, I’ll show you how much additional RAM you will need for Photo Editing:
How much RAM does Photoshop need?
This is how can you find out how much RAM you are currently using for Photoshop and how much you will probably need depending on your use case.
After a fresh start of Photoshop, without having any Photos open, the Software itself needs 262MByte of RAM. Start your Task Manager and see for yourself:
Now after opening a 5MByte JPG 12MP 8bpc (bits per channel) Image, my RAM usage increases to 369 MByte.
Why does it increase over a 100 MByte? My Image File Size is only about 5 MByte?
Well the answer is, your Photo Editing Software decompresses any compressed Image File types to make them editable.
JPG is a compressed Image file type, as are PNG and GIF. By using algorithms, the Software is able to decrease file-size, without loosing noticeable Quality. An Image of course can only be compressed so much until a quality loss is noticeable.
The reason why a Photo Editing Software decompresses an Image while you edit it, is because your photo manipulations are done on a pixel basis, and having to compress the Image after every pixel-change, will make the editing very slow and CPU intensive.
Another factor for calculating how much RAM you need to edit an uncompressed Image, is Bit Depth.
Typically you edit your Images in RGB mode, meaning you have three channels (R, G and B) and every channel will be able to save 8 bits, or 256 different values. 8 bits per channel, 256 Values per Channel (or Color). All your JPG Images are in 8bpc or 24bpp (bits per pixel).
The next important factor of course is the Image Resolution. The Math actually is quite easy:
[Pixel Amount in Width] x [Pixel Amount in Height] x [Bit Depth] x [Number of Channels] divided by 8000000
Why 8 Million? Because 8 Bits are one Byte and a Megabyte are 1000000 Byte.
This will give you the Uncompressed Image Size in MByte that resides in your RAM. If you only have one Layer!
Layers in Photoshop
If you have more than one Layer, you can roughly multiply the amount of RAM usage per Image by the amount of Layers.
Also, in Photoshop you can easly find how much RAM your uncompressed Image is currently using by looking in the bottom left corner. The first number is without Layers, the second with all Layers accounted for.
How much Ram do you need for Photoshop?
Ok this was difficult enough, let’s look at this table, where all Important factors above have already been considered:
|8MP||24 MByte||30 MByte||48 MByte||96 MByte|
|12MP||36 MByte||45 MByte||72 MByte||144 MByte|
|16MP||48 MByte||60 MByte||96 MByte||192 MByte|
|20MP||60 MByte||75 MByte||120 MByte||240 MByte|
Great, now you can roughly estimate or calculate how much RAM a single Image will need.
Now, to truly estimate How much RAM you will need for Photo Editing all you have to think about is:
- What Bit Depth do I edit Photos in (usually 8Bpc for JPGs, 16bpc for RAW Files)
- How many Photos do I have open at the same time
- How many Layers do my Photos usually have on average
- How much RAM does my System need in addition
That said, if you dont want to calculate it yourself but just want some quick recommendation here it is:
On Win 10 and Photoshop, 8 – 16GByte of RAM will be more than enough for most of your tasks when editing JPG Photos in the 10 – 20MP range and the occasional RAW Image.
If you are a power user, that edits mainly in high Bit depths and Resolutions, and might have lots of other RAM intensive Software running in the background, consider 32 GByte.
Thats about it, have I missed anything? Let me know in the comments.